Problem with Sockets

Hi buddies, How are you !!

I got the following problem while i am developing a chat software

My software consists of two parts:

Server
Client

each in a seperate project, and each works very well when they are working alone, but when i try to test my application -I run the server then the client- i got the problem that when the client create the TcpClient object i got this message:

Only one usage of each socket address (protocol/network address/port) is normally permitted

I think that is because i use the same port number for both applications but this is the only way to run both applications on the same machine.

the short version of my question is:

How can I start a TcpListener and a TcpClient on the same machine and the same port

I tried all the windows registry things but no change accured,

Thanks in advance.

Answer this question

Problem with Sockets

Raulsassaa

Hi Timvw,

yes my server binds the ip/port, and my client use a TcpClient to connect to the server, i think this is the normal way to do it, is there any way to connect to the server without using the TcpClient bound to the port
Hassank
Could you show us the code please

server:
```
IPAddress ipAddress = IPAddress.Parse("127.0.0.1");
```
int port = 54321;

TcpListener tcpListener = new TcpListener(ipAddress, port);

// start, acceptsockets, close, ...

client:

TcpClient tcpClient = new TcpClient();
tcpClient.Connect("127.0.0.1", 54321);

// read, write, close, ...
DavidThi808
If you're sure your firewall(s) and network configuration are accepting incoming connections on that ip:port than you should verifiy if the server is really running ;)

(netstat -an might be helpful)
Kunal Sharma
Hi Peter

I just tested this:

Server:

TcpListener tcpl = new TcpListener(IPAddress.Any, 101);

public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{
tcpl.Start();
tcpl.AcceptTcpClient();
}

Client:

TcpClient tc = new TcpClient("localhost", 101);
bool x = tc.Connected;

x became true (no error or something else)

Could it be that you have 2 server instances running or that some other application is already running on that specific port (skype always listens at port 80 for example)
gifuran

Hi Tim, Hi Thomas

My server code is something like this:

this.listener = new TcpListener(IPAddress.Loopback, 12554);

this.listener.Start();

while (true)

{

try

{

this.socket = this.listener.AcceptSocket();

this.stream = new NetworkStream(this.socket);

this.reader = new BinaryReader(this.stream);

this.writer = new BinaryWriter(this.stream);

if (this.Authenticate())

this.Redirect();

}

catch { }

}

and it run in a seperate thread

my client code is:

System.Net.IPEndPoint ee = new System.Net.IPEndPoint(System.Net.IPAddress.Loopback, 12554);

TcpClient cl = new TcpClient(endPoint);

try

{

this.stream = cl.GetStream();

this.reader = new BinaryReader(this.stream);

this.writer = new BinaryWriter(this.stream);

}

catch

{ }

I am sure the problem is not because another application is using this ip/port, because the exception doesn't happen when i don't start the server

When i compiled the code with .NetFX 1.1(VS 2003) the problem didn't accur
jeff357

When i used the Connect method, the old exception didn't happen but a new one happens that says that the target machine refuses the connection, i checked my network configuration and my firewall setting and still got the same message

if you have evered experienced that please help me, thank you :)
j_o_h_a_n_n_e_s
If you use the TcpClient constructor that accepts an IPEndPoint you will bind to that address...

The following code should do what you want:

TcpClient cl = new TcpClient();
cl.Connect(endPoint);
vije
To me it seems that both your server and client are trying to bind to the same ip:port combination... Only the server should bind to a socket.. And the client should then connect/open (but not bind to) that socket...
Problem with Sockets

Answer this question